1. Field of the Invention
The invention relates to aircraft fasteners; and, more particularly, to a fastener having a magnetically actuated positive lock plug insert in its head eliminating any cavities or holes in the head while providing a positive lock therein.
2. Related Art
Various types of aircraft fasteners are known in the art. In my U.S. Pat. No. 4,822,227, commonly assigned, I disclosed fastener assembly for joining a panel to a sub-panel of an aircraft or the like comprising a receptacle assembly having a threaded stud secured to the undersurface of the sub-panel. The assembly includes a bolt having an enlarged head at one end and a nose at the other end. The panel has a countersunk opening aligned with an opening in the sub-panel. The bolt is threaded for threaded engagement to the stud. The head of the bolt has a countersunk opening configured to a tool for rotating the same. This opening includes a releasable plug which is moved downwardly upon insertion of the tool to permit rotation thereof, then returns to a position flush with the exterior of the head of the bolt surrounding the opening.
A spring is used to bias the plug to a position wherein the upper surface of the plug is flush with the bolt head surrounding the countersunk opening in which the plug is disposed. This spring can wear or become clogged during use and may not return the plug to its fully flush position leaving a slight recess or cavity on the bolt head. In addition, overtorquing of the bolt by the user may distort the recess or cavity on the bolt head and create burrs on top of the bolt head. Such slight cavities or recesses or burrs may be detected by sophisticated radar if the bolt is installed on an aircraft panel.
There is a need for a fastener having a removable head plug in its bolt head that is positively locked therein and can be easily removed when it is desired to remove the bolt.
It is an object of this invention to provide an improved fastener having a plug closing off a hex socket or the like in the bolt head which is positively locked therein and removable using magnetic means.
It is a further object of this invention to provide a fastener having a removable head plug positively locked into a socket in the bolt head using ball locking means.
It is still further an object of this invention to carry out the foregoing object wherein the plug has a locking element of metallic material so it can be quickly and easily removed using a magnet.
These and other objects are preferably accomplished by providing a fastener having a removable head plug so that no cavities are visible or detectable in the fastener head.
These and other objects are preferably accomplished by providing a fastener including a bolt having a plug positively locked into the bolt head and any cavities in the bolt head are eliminated. The plug cannot come out during high vibrations. The plug may have an internal locking element of a metallic material or include a magnetic material in said element so that magnetic means can be used to remove the plug to replace the fasteners.